A number of NASL, USL Pro and PDL teams are nearing 25 years of existence. Year given is first year the team started to play. USL Pro Western Conference 1.Arizona United SC 2014- 2.Austin Aztecs 2015- 3.Colorado Springs Switchbacks 2015- 4.Los Angeles Galaxy II 2014- 6.Oklahoma City Energy FC 2014- 6.Orange County Blues 1999- (Los Angeles Blues, PDL 1999-2010, USL-Pro 2011-2013, Orange County Blues 2014-) 7.Portland Timbers II 2015- 8.Real (Salt Lake) Monarchs 2015- 9.Sacremento Republic 2014- 10.Seattle Sounders FC II 2015- 11.Tulsa Roughnecks FC 2015- 12.Vancouver Whitecaps FC II 2015- Eastern Conference 1.Charleston Battery 1993- (USISL 1993-1994, USISL Pro 1995-1996, A-League 1997-2004, USL First Division 2005-2009, USL Second Division 2010-, USL Pro 2011-) 2.Charlotte Independence 2015- 3.FC Montreal 2015- 4.Harrisburg City Islanders 2004- (USL Pro 2004-, USL Second Division 2005-2010, USL Pro 2011-) 5.Louisville City FC 2015- 6.New York Red Bulls II (no official name yet) 2015- 7.Pittsburgh Riverhounds 1999-2006 2008- (A-League 1999-2003, USL Pro 2004-, USL Second Division 2005-2006 2008-2010, USL Pro 2011-) 8.Richmond Kickers 1993- (USISL 1993-1994, USISL Premier 1995, USISL Select 1996, A-League 1997-2004, USL First Division 2005, USL Second Division 2006-2010, USL Pro 2011-) 9.Rochester Rhinos 1996- (as Rochester Raging Rhinos 1996-2008) (A-League 1996-2004, USL First Division 2005-2009, D2 2010, USL Pro 2011-) 10.St Louis FC, 2015- 11.Toronto FC II, 2015- 12.Wilmington Hammerheads 1996-2009 2011- (USISL Pro League 1996, D3 1997-2002, USL Pro Select League 2003-2004, USL Second Division 2005-2009, USL Pro 2011-)
Aztex, not Aztecs. And they didn't just start playing this year, they've been in the PDL. Sacramento, not Sacremento. And there was no Los Angeles Blues team in the PDL from 1999-2010. There was a Pali Blues team in the W-League for years and now OC has a PDL team, but I am not sure which club you believe became the Los Angeles/Orange County Blues pro team.
And I guess you are meaning CONTINUOUS play, because there was a Tulsa Roughnecks in the USISL in 1993
And in the D3 Pro League in 1997. But that doesn't mean they're 22 years old. Of course it's continuous (or nearly) play.